This is all well and good, but there are still a couple problems. Problem number one: Are the Bio-Fuel farmers actually doing this, and Two: Can you efficiently extract the required components form the grasses?

A brief note on our agricultural community. For one, in times of abundance our government actually pays farmers to let their crops go into decay rather than sell them to the public. So, in short it's not like we have a shortage, it's just another arguement to back oil companies.

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the problems (and the debate) about Biofuels vs. Food comes ONLY from the fact that all countries and companies choices always are for the simplest and most profitable way to solve the problems

then, they try to change the FUEL rather than change the CARS

we know that EACH DAY our Sun send us an incredible amount of FREE energy and that LESS than 1% of that daily energy is enough to cover ALL the world daily energy needs

now we have the technology to capture the solar energy (as light and wind) and the good news is that it's also a CHEAP technology, so, if politics and industries WANT, we can use agricolture for FOOD and the SUN for energy

maybe... using some SMARTER, cheaper and MORE "energy dense" power plants like MY "Wind Energy Skyscrapers Power Plants":

http://www.gaetanomarano.it/articles/028energy.html

if many science magazines and websites like POPSCI.COM will talk and write articles on them, maybe, somebody will develop and build this new kind of energy source... :)

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The current food price hike is due to short term market forces of supply and demand.

The real question is in the long term can current and easily accesible agricultural land support both world food production and bio fuel production.

I think this is an issue that needs much deeper study than a few speeches at a conference. The big picture is that in the long term, any significant use of bio-fuels will either result in a fall in food production or an increase in agricultural use of land. Scientists from different sectors need to work together to decide if the net effect on Carbon emissions justifies the cost in terms of food prices and damange to vegitation.

Also scientists need to consider alternate power sources including solar, and more efficient power production, and tell consumers what is best for the world as a whole.

I also wonder why the mentioned technique is not in commercial use. Is there serious bottleneck in the process or is it simply just a new process yet to be commercialised.

Mr. Tilman may be right in that the future of biofuels has much less of an impact on our food supply. However, cellulosic ethanol is not a present reality. The current situation is that we have politicians and agriculture lobbyists out there pushing corn based ethanol as if it's the solution to all of mankind's energy problems. And the result is that we get a lot of people who don't know the reality of the situation piling on the bandwagon which causes all of these problems with food supplies right now.

What we need from people like Mr. Tilman is to cut through all the hype, and educate politicians and investors that biofuels, while very promising, are not quite ready for the spotlight.

When cellusic ethanol moves out of those test fields in Minnesota and into a commercial atmosphere, then Mr. Tilman's speech will have relevance. Until then though, he's just compounding the problem.

So, picking up grass cuttings from "infertile" land is going to be 238% MORE efficient than corn. NOT 237%, NOT 239%, 238%. Well, let's see. Corn grows to 8 feet tall and produces a fruit that weighs about a pound each and may have 5-8 per plant. Yield averages about 6.5 TONS per acre. Various grass on unfertilized, unwatered, infertile land might be 2 feet high. What do you think the yield will be? It ain't gonna be 15 TONS! Maybe ONE. And how is this to be harvested? You are talking about YARD CLIPPINGS. It would be more efficient to pick them up with a WHEEL BARROW. Certainly not a harvester.

So maybe this whole article is just one big BLOWING SMOKE BS puff piece.

DRILL ANWAR! And the coasts. THAT will bring us "energy independence". You can't "conserve" a tank of fuel.

Coskata has a process that uses anything organic (everything from switchgrass to garbage) and produces almost 7 times as much fuel as it consumes - fermenting corn is at best a break-even process.

http://oblate-spheroid.blogspot.com/2008/01/bacteria-delivers-buck-gallo...

It is unfathomable why people would waste food for biofuel when there are so many better alternatives.

Lets see, a bunch of "biomass" engineers and scientists conclude that ethanol is not a problem. I'm shocked! What else would they conclude? Follow the money, folks.

Mr. Tilman claims that the best agricultural non-food energy yields come from prairie grasses. However, what energy is he talking about? Is it the total energy content of the prairie grass? If so, how would it benefit us, would it replace coal in an electric power plant? Would the harvested prairie grass be fermented to ethanol or butanol using some yet to be invented process? How much energy would be required to grow and to process prairie grass to useful fuel or useful energy? Would there be a net increase in energy in the process? How many harvests of prairie grass could be tolerated before the soil is depleted of minerals and nutrients? How many acres of marginal arable land would be required for prairie grass production in order to replace just 5% of our transportation energy needs with the energy derived from prairie grass? Mr. Tilman proposes and answers none of these questions. There is no substance to Mr. Tilman’s article, just fluff. In many ways Mr. Tilman is like Barack Obama, a lot of meaningless words and no substance, just promises.

Unfortunately, in the last few years, articles such as this have significantly decreased the stature of this once-great popular science magazine. I concluded long ago that Popular Science has an agenda that is not compatible with good science and economics.

Jose Sanchez

It doesn't matter what they make ethanol of. The problem is it requires a b-load of space to produce it in the quantities needed. This leads to deforestation i.e. brazil (now the 4th largest carbon emitter in the word due to BURNING the rain forest to grow crops). Ethanol is not the solution.